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(No Modem T. CURRAN. MOLD FOR MAKING PLASTBR SLABSA. No. 442,957. Patented Deo. 16

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l l I I y UNITED STATES PATENT QEErCE.

THOBIAS CURRN, OF NEIV YORK, N. Y.

MOLD FORMAKINGPLASTER SLABS.

SPECIFICATION forming part of Letters Patent No. 442,957, dated December 16, 1890.. Applicatien filed March 11, 1890. Serial No. 343,474. (No model.)

To all w21/011e it may concern.'

Beit known that I, THOMAS CURRAN, a citizen of the United States, residing in the city, county, and State of New York, have invented certain new and Improved Molds for Making Plast-er Slabs, of which the following is a specification.

The invention relates generically toa mold for forming plaster slabs or sections of composite material, which are adapted to be attached to the interior Walls or ceilings of buildings, and they are so constructed as to be adapted for the reception of further and finishing coats whereby the sectional lines or divisions are entirely obliterated and a strong, durable, and-economical result obtained.

In carrying out my above invention I provide a suitable rectangular frame, and in connection therewith I employ a flexible molding piece or sheet having longitudinal wooden or other strips inserted in the face thereof, and so arranged as to protrude in relief above the normal snr-face of the said flexible molding-sheet, whereby when it is applied to a plastic compound contained within the aforesaid frame the longitudinal stripsV will embed themselves in the plaster and will form corresponding and complementary openings or grooves therein, which will be utilized for the lpurposes hereinafter set forth.

Referring to the accompanying drawings, which form apart of this speciiication, Figure I represents'a transverse section of the plaster-containing frame, in which is inserted a body of plaster and a iiexible molding-sheet. Fig. II is a face view of the ilexible'moldingsheet. Fig. III represents a plaster slab completed and after it has been removed from the frame and the moldingsheet has been withdrawn and it has been attached by any suitable means to the wall. The coatings of mortar and hard finish are also shown in this view. Figs. IV, V, VI, and VII are sectional views of various forms of the plaster slab. Fig. VIII showstwo slabs side by side, illustrating how they are to be arranged so as to provide for the continuity of the grooves.

In the drawings, A represents a frame, which may be of wood, iron, or othersuitable material.

B is a flexible molding-sheet, and it may be formed of cloth or canvas and itis preferably longitudinal openings, grooves, or recesses corresponding with the raised molding-strips on the flexible molding-sheet aforesaid, the cross-section and conformation of said openings, grooves, or recesses depending upon the size and nature of the raised strips or ribs on the flexible molding-sheet.

The method of carrying' my invention into effect is as follows: The flexible moldingsheet I3 is spread with its uneven face up-` ward on a suitable horizontal table or support A', and the molding-frame A is then placed in position on top of Athe moldingsheet, so that the sides of the frame will be parallel to and the ends of the frame at right angles with the raised strips or ribs R o f the molding-sheet. The plaster is then introduced in the receptacle formed by the walls of the frame andthe molding-sheet, and after a sufficient amo-unt has been inserted the plaster is smoothed over on the top of and within the frame and gently pressed, so as to embody the ribs or molding-strips in the body of the plastic material. IVhen the plaster is hardened, the frame and its contents are turned over and one edge B of the flexible molding-sheet B is raised, and if the molding strips or pieces are of a nature such as hereinafter described the whole sheet may be removed by simply drawing it in this man ner from one side of the fra-me to the other. After the slab has been subjected to a drying process it is ready for use.

It will be seen in the above drawings that I construct my moldingribs of various sizes in cross-section, thepurpose being to form grooves or longitudinal recesses of various shapes, according to the demand of the trade, some being desirable in heavy work and others in lighter work. For example, the construction shown in Fig. III represents a IOS plaster slab formed in the manner above described and according to my invention attached to a wall of a room or a building, the grooves or longitudinal receptacles being lshown in cross-section. rlhese grooves, it will be seen, are so constructed as to support the ordinary rough brown mortar H, inasmuch as the grooves or longitudinal receptacles will form pockets or supports for the plastic mortar and will serve the same purpose as the open laths heretofore employed, and by this means the said mortar will be fully supported by the plaster slab, as shown. After the rough mortar II has been applied the coating or finish I may be put on.

As above stated, I may vary the form of the grooves or longitudinal receptacles, according to the nature of the work for which the slabs are intended.

In Fig. IV, I show a section of slab having grooves or longitudinal openings, of which one series of sides are dovetailed and the other nearly or approximately at right angles to the face of the slab. I depart slightly from the right angle, so as to make the {iexible sheet the more easily removable. In making these slabs and withdrawing the flexible molding-sheet provided with the ribs hereinbefore described the said sheet when raised will come oft' easily without the separate removal of the ribs. The same may be said of the form of plaster slab shown in Fig. Y. Both of these forms of slabs are of value in the construction of walls, as I intend to use them in the manner shown in Fig. III, with the angle of the dovetailed portion pointing downwardly, and it will be seen that two of these grooves taken together form a lock, and that the mortar after being once inserted and thoroughly dried will be as [i rml y held by means of these grooves and their overhanging corners as in the case of the ordinary woodenl lath, and even in some cases much better7 as what are known as the keys of the plaster will not in the ease of my in vention be liable to break off.

In Figs. VI and VII, I show modifications where the dovetail extends to both sides of the groove or longitudinal receptacle, and in manufacturing these forms it is necessary to withdraw the wooden strips or ribs R from the flexible molding-sheet after the slab has been formed and before the said sheet is removed. The ribs or strips of wood R can be withdrawn endwise by drawing them out of the pockets in the molding-sheet, and after they all have been removed the flexible molding-sheet can be drawn off, leaving the slab with the dovetail grooves or openings7 as shown in Figs. VI and VII, according to the shape of rib employed.

It will be seen by referring to Fig. III that the slabs or sections are attached to the wall, and that the after coatings of brown mortar and superimposed white hard finish obliterate the dividing-lines.

As will be seen by referring to Fig. VIII, the slabs when arranged end on the grooves G in the said slabs will register with each other, thus establishing their continuity and providing a very enduring support for the superimposed coa-t of mortar.

Having thus described my invention, the following' is what I claim as new therein and desire to secure by Letters Patent:

I. A iiexible molding-sheet for making plaster slabs, provided with ribs or raised portions, in combination with an inclosing frame, as and for the purposes set forth.

2.. A mold for making groovedplaster slabs, which consists in. a frame for containing the plaster, a flexible moldingshcet provided with raised ribs inserted in the face thereof, the said ribs being beveled on their edges so as to produce dovetailed grooves or openings in the plaster slab, as set forth.

3. A mold for making grooved portable plaster slabs, which consists in a frame for containing the plaster and a flexible moldingsheet provided with raised ribs inserted in the face thereof, said ribs being removable, as and for the purposes set forth.

THOMAS CURRAN.

Witnesses:

HERBERT KNIGHT, GEORGE S. BELL. 

